When a vote on any motion is called for, the mayor or other presiding officer may call for a voice vote and may determine whether any such motion carried or failed; any member of the city council, however, may call for a roll call vote on any motion. All votes on motions for passage of any ordinance or resolution shall be called for by the city clerk by calling the name of each member present including the mayor; each member shall be recorded as voting "aye" unless when his name is called he votes "no" or declares he is not voting. Unless a member of the city council states he is not voting because of a personal interest in the subject matter under discussion, his silence shall be recorded as an affirmative vote. (Ord. 728, 12-12-1989)